1. Field of the Invention
The present invention relates to disk drive systems, and more specifically, to redundant array of independent disks (RAID) system backup management.
2. Description of Related Art
RAID is a technology used to improve the input/output performance and reliability of mass storage devices. A RAID array incorporates fault tolerance by using a redundant architecture, and the disk controller which controls a RAID array may be referred to as a RAID controller. In RAID systems, data is stored across multiple storage units (e.g., disks in order to provide immediate access to the data despite the failure of one or more storage units. Data is distributed across the storage units in one of several ways called “RAID levels,” depending on the level of redundancy and performance required. The different RAID schemes or architectures are named by the word RAID followed by a number (e.g., RAID 0, RAID 1, etc.). Each scheme can provide a different balance between reliability, availability, performance, and capacity.
RAID 5 distributes parity along with the data and requires all storage units but one to be present to operate. The array is not destroyed by failure of a single storage unit. Upon drive failure, any subsequent reads can be calculated from distributed parity such that the storage unit failure is masked from the end user. Systems running large-capacity, storage units in RAID 5 can encounter long rebuild times in the event a storage unit fails and the array needs to be rebuilt. This problem is prevalent and noticeable in the information technology (IT) industry for example. For at least this reason, there is a need for systems and techniques that improve the reliability of RAID systems and the time in which they can be rebuilt after failure.